A. Just as hidden cameras show people smile little when alone, a dog won't wag to a lifeless room but will to other dogs, people, a cat, a horse or even a mouse or moth, says Dr. Stanley Coren in What Do Dogs Know?

So wags like smiles are social communiques– possible evolutionary reason for the highly visible white-or-dark-tipped tails of so many breeds.

There are wags of greeting, liking, play, puzzlement, relief. An exuberant wag may express gratitude as you put down a food bowl, but should the dog come into the room and encounter a full bowl, it will eat just as pleasurably but wagless, except perhaps for a small tremor.

Q. Imagine advanced aliens 65 million light years distant aiming a superpowerful telescope Earthward. What do they see? Dinosaurs as they were 65 million years ago, or just a blue spot? –D. Scott

A. It is true that the light arriving right now at a planet 65 million light years away left Earth 65 million years ago, when dinosaurs were still around, says Clemson astrophysicist Bradley Meyer. This means a large enough telescope would, in principle, be able to see them.

However, it is mind boggling to realize how large that telescope would have to be. The resolution of a telescope– how well it can distinguish two points from a given distance– is proportional to the diameter of its mirror.

The Hubble Space Telescope (HST) has fantastic resolution: If it were sitting in New York City, it could see and distinguish two fireflies 1 meter (3.3 feet) apart in San Francisco!

But even with that resolution, HST can't resolve in much detail individual stars in a galaxy 65 million light years away, far less can it see planets, says Meyer. To see the Earth from that distance would require a telescope with a mirror some 13 billion times bigger in diameter than HST (42 times the diameter of the Moon's orbit around the Earth). And to see dinosaurs would require a telescope roughly 40 light-years in diameter!

Q. Do you happen to know the nationality of the guy who invented the telephone? –M. A. Bell

The famous inventorship dispute of 1876 pitted Alexander Graham Bell vs. Elisha Gray, though a number of others actually beat the famous duo to the punch by several years: French accounts tend to emphasize Charles Bourseul's theoretical underpinnings of the phone (1854); many Italians consider Antonio Meucci to be the real inventor with his 1857 operational model; Germans cite the 1860 electric telephone by Philipp Reis.

Bell is championed in his home country of Scotland, his adopted home Canada, and in the U.S., where he became a citizen six years after filing his patent. Unlike his predecessors, Bell was able to create a successful phone company, netting him money and the PR resources to promote himself as the inventor.

Apparently, when the time is ripe for an invention, it tends to be pursued in many places. Yet at least in popular culture, much of the credit is bestowed on the last contributor, even when the essential original insights came from others. "As they say, Columbus did not become famous because he was the first to discover America," Schmidhuber says, "but because he was the last."

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Send strange questions to brothers Bill and Rich at strangetrue@compuserve.com.